How to run a GUI software as a different user (Debian 10)?

Question

In Debian 10, how do I run software with a graphical user interface as a different user?

Trying to separate let's say private data and work data, but occasionally need to run software from the other user. Switching users is kinda cumbersome and in most cases I don't want to lose access to opened windows from private while I check software of work.

Answer 1

Any running Xorg application, unless it's running under Xnest, is able to grab the entire screen and read all mouse/touchpad events and key presses.

If you believe running under a separate user under the same X session has any security benefits in terms of interacting with your graphical session, you're wrong. The new user however will not have access to your files.

Wayland fully isolates graphical applications from one another but I'm not sure if Debian properly supports Wayland.

You can learn how to use Xnest here.